Facial mask and method of making

ABSTRACT

Masks for various uses and methods for manufacture thereof, including masks for use in continuous positive air pressure (CPAP) therapies. An example includes a mask having a first, relatively softer material for contact with the face of the user, and a second, relatively harder or more structural material used away from the face of the user, with a gradient therebetween. The mask can be produced by additive manufacturing to avoid a discernible boundary between the first and second materials.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application claims the benefit of and priority to each ofU.S. Provisional Patent App. No. 61/950,591, filed Mar. 10, 2014 andtitled FACIAL MASK AND METHOD OF MAKING, and U.S. Provisional PatentApp. No. 62/010,528, filed Jun. 11, 2014, and titled FACIAL MASK ANDMETHOD OF MAKING, the disclosures of which are incorporated herein byreference.

BACKGROUND

Millions of people in the U.S. suffer from obstructive sleep apnea (OSA)with a prevalence of 20-30% in men and 10-15% in women. OSA is acondition where the upper airway collapses during sleep andsignificantly limits or obstructs air entry into the lungs. The mainstayof treatment for OSA is continuous positive airway pressure (CPAP). Thisworks by simply applying positive air pressure to the upper airway whichconsists of the nasal passages, mouth, nasopharynx, oropharynx, andhypopharynx. CPAP pressure opens the upper airway, allowing the sleeperto breathe easily without intermittent obstruction and interruption ofairflow into the lungs.

CPAP pressure is delivered via a mask applied over the nose (nasal mask)or over the nose and mouth (full face mask) with air pressure tubingrunning from the mask to a CPAP machine. A good mask seal is desirableas high leak rates from air escaping around the sides of the mask areuncomfortable and may disrupt sleep. High leak rates may also cause CPAPtreatment to be ineffective.

Some sleepers find using a mask at night uncomfortable and so havedifficulty sleeping with one. Further, some sleepers will easily fallasleep using a CPAP mask only to discover that sometime during the nightit has come off or that they have removed it surreptitiously. Theseproblems clearly make CPAP therapy less effective than it otherwisemight be.

A process whereby a more comfortable and effective mask with lower leakrates could be easily manufactured would be a great advancement in thetreatment of OSA and other forms of sleep disordered breathing.

Such an advancement would also benefit the manufacture of other medicalmasks and certain other medical facial apparatus such as oxygen masksused for surgery and in recovery, masks used for delivery of gaseousmedicaments, and the like such as for dental or surgical procedures;“nasal pillows”, circumferential fittings for the nasal inlets;additionally, non-medical masks such as snorkeling or diving masks wouldbenefit from increased comfort and a better seal, which would lower theegress rate of water into the mask during use.

Such an advancement would also benefit the manufacture of other articleswhere differential pressure in contact with the human or animal body cancause discomfort.

OVERVIEW

The present inventor has recognized, among other things, that a problemto be solved includes the provision of masks for various uses includingCPAP having gradual transitions from one material property to another.Several solutions to this problem may be realized by embodiments shownbelow, some of which can be fabricated by the use of facial imaging andthree-dimensional printing (“3D Printing”).

A first example takes the form of a facial mask comprising a firstmaterial and a second material and a material gradient in at least aportion of the mask, the material gradient transitioning from the firstmaterial to the second material. A second embodiment is a facial mask asin the first example, wherein the first material is a polymeric materialsuited to a first purpose, and the second material is a polymericmaterial suited to a second purpose and not to the first purpose. Athird example takes the form of a facial mask as in either of the firsttwo examples, wherein the first material is a relatively softer materialwell suited to contact with the face of a patient, and the secondmaterial is a harder material well suited to providing a structure andshape to the mask.

A fourth example is a facial mask as in any of the first three examplesfurther comprising two or more gradients. A fifth example is a facialmask as in any of the first four examples, wherein the first and secondmaterials differ in one or more of modulus, elasticity, glass transitiontemperature, degree of crystallinity, ductility, softening point, ormelt flow index. A sixth example is a facial mask as in any of the firstfive examples, wherein the mask is a CPAP mask. A seventh example is afacial mask as in any of the first six examples, wherein the mask ismade by additive manufacturing without the use of insert molding orcasting.

An eighth example is a facial mask as in any of the first seven exampleswherein the material gradient or gradients are characterized by a lackof discernible boundary insofar as there is no visible boundary to thenaked eye. A ninth example is a facial mask as in any of the first eightexamples wherein the material gradient or gradients are characterized bya lack of discernible boundary insofar as a boundary cannot beidentified under manual inspection.

A tenth example takes the form of a method of manufacturing a facialmask, the method comprising obtaining a set of facial contours of aperson's face by one or more of digital photography, video, infrared, orlaser scanning; optimizing a set of mask contours for an area where amask will come in contact with the person's face; and constructing amask using an additive printing process including a first layer of afirst material having first properties and a second layer of a secondmaterial having second properties and a material gradient between thefirst and second layers in at least a portion of the mask, the materialgradient characterized by the lack of a discernible boundary between thefirst and second materials.

An eleventh example is a method as in the tenth example wherein theconstructing step is performed such that the first material is apolymeric material suited to a first purpose, and the second material isa polymeric material suited to a second purpose and not to the firstpurpose. A twelfth example is a method as in either of the tenth oreleventh examples wherein the constructing step is performed such thatthe first material is a relatively softer material well suited tocontact with the face of a patient, and the second material is a hardermaterial well suited to providing a structure and shape to the mask. Athirteenth examples is a method as in any of the tenth to twelfthexamples wherein the constructing step is performed by introducing athird material having third material properties different from each ofthe first and second materials and joining the third material to atleast one of the first and second materials using at least a secondgradient characterized by a lack of discernible boundary to the firstand/or second materials.

A fourteenth example is a method as in any of the tenth to thirteenthexamples, wherein the constructing step is performed using first andsecond materials that differ in one or more of modulus, elasticity,glass transition temperature, degree of crystallinity, ductility,softening point, or melt flow index. A fifteenth example is a method asin any of the tenth to fourteenth examples wherein the constructing stepis performed without the use of insert molding or casting. A sixteenthexample is a method as in any of the tenth to fifteenth examples whereinthe additive process is performed such that the material gradient ischaracterized by a lack of discernible boundary from the first materialto the second material insofar as there is no visible boundary to thenaked eye from the first material to the second material.

A seventeenth example is a method as in any of the tenth to sixteenthexamples wherein the additive process is performed such that thematerial gradient is characterized by a lack of discernible boundaryfrom the first material to the second material insofar as a boundarycannot be identified under manual inspection. An eighteenth example is amethod as in any of the tenth to seventeenth examples wherein the stepof optimizing a set of mask contours comprises identifying one or morefiducial points of the set of facial contours associated with one ormore of the patient's nose, lips, or eyes and setting an inner boundaryand an outer boundary relative to the identified fiducial point orpoints.

A nineteenth example takes the form of a continuous positive airpressure facial mask for the treatment of sleep apnea built according toa method as in any of the tenth to eighteenth examples.

This overview is intended to provide an overview of subject matter ofthe present patent application. It is not intended to provide anexclusive or exhaustive explanation of the invention. The detaileddescription is included to provide further information about the presentpatent application.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings, which are not necessarily drawn to scale, like numeralsmay describe similar components in different views. Like numerals havingdifferent letter suffixes may represent different instances of similarcomponents. The drawings illustrate generally, by way of example, butnot by way of limitation, various embodiments discussed in the presentdocument.

FIG. 1 is a flow chart for an illustrative method;

FIG. 2 illustrates a patient wearing a nasal mask;

FIGS. 3A-3E show several designs for nasal masks;

FIG. 4 illustrates a patient wearing another nasal mask;

FIG. 5 illustrates a patient wearing a full-face mask;

FIG. 6 illustrates a patient wearing another nasal mask;

FIG. 7 shows an orthotic embodiment of the present invention; and

FIG. 8-10 illustrate configurations for varying flexibility of anarticle;

FIGS. 11-12 show illustrative tissue contact designs;

FIG. 13 illustrates a mask having an attachment feature and air tube forcoupling to a CPAP machine;

FIG. 14 shows an illustrative working example;

FIG. 15 shows an illustrative example of the selecting of inner andouter boundaries based on identified fiducial points; and

FIG. 16 shows another illustrative working example.

DETAILED DESCRIPTION

Although the present disclosure provides references to preferredembodiments, persons skilled in the art will recognize that changes maybe made in form and detail without departing from the spirit and scopeof the invention. Various embodiments will be described in detail withreference to the drawings, wherein like reference numerals representlike parts and assemblies throughout the several views. Reference tovarious embodiments does not limit the scope of the claims attachedhereto. Additionally, any examples set forth in this specification arenot intended to be limiting and merely set forth some of the manypossible embodiments for the appended claims.

Described herein are a series of mask or orthotic articles, related bythe common principle that the articles are formed to contact the surfaceof a human or animal body. In some embodiments, articles arecharacterized by one or more material gradients incorporated integrallywithin the article for the purpose of providing increased comfort,better fit, and the like. A gradient includes at least two differentmaterials having distinctly different material properties such asmodulus, ductility, and the like, wherein the materials are changed overfrom at least first to second relative compositions without adiscernible boundary therebetween. Hence, as used herein, the term“gradient” means having a substantial lack of a discernible boundary orinterface between areas of different composition. For example, agradient may span from a first region substantially made of a firstmaterial to a second region substantially made of a second material,with the gradient gradually transitioning (in stepwise or continuousmanner) from the first material to the second material, without adiscernible boundary. In another example, a gradient may span from afirst region of a first blend of materials to a second blend ofmaterials, with the gradient gradually transitioning (in stepwise orcontinuous manner) from the first blend to the second blend, without adiscernible boundary. The articles described herein have non-gradientregions and gradient regions in some embodiments. In some embodiments,the articles have two or more gradient regions. Gradients include bothlinear gradients and non-linear gradients.

Gradient articles can be suitably formed using a 3D printer employingtwo or more materials that are capable of providing different propertiessuch as modulus, ductility, and the like. In some embodiments, thematerials delivered are UV curable compositions that are delivered, orprinted, in substantially liquid form, then solidified by UV irradiationthat initiates one or more polymerization and/or crosslinking reactionsin the printed compositions. Fine structures can be suitably formed withmixtures of materials at continuously changing ratios, which in turnleads to a material gradient. Gradient changes may be stepwise as well,with the intention being that the steps occur without discernibleboundary to a user viewing an article or portion thereof with the nakedeye or manually inspecting an article or a portion thereof. Computeralgorithms aid in determining the proper ratios of materials to providethe desired gradient. Such gradients are suitably linear or nonlinear,monodirectional or multidirectional (horizontal, vertical, radial, ormore than one of these).

Increased comfort can be achieved for articles contacting the human bodywhen gradient differences are employed, when compared to similararticles that employ a blend of materials wherein no gradient betweenmaterials is present. Additionally, providing a gradient of materialsreduces the wear and tear that occurs at sharp interfaces and boundarieswhere the article is subjected to relatively high stress, rapidmovement, or both. These and other benefits of providing materialgradients in articles that contact the human body surface will bereadily apparent through the description of several specific examples.The examples described below are intended to be only representative ofmany embodiments that are possible, as will be appreciated by one ofskill in the art.

Described herein is a method of fabricating custom-made CPAP masks, anda custom-made mask that includes one or more material gradients.Fabricating a CPAP mask that conforms to the shape of a sleeper's facedecreases leak rates, improves comfort, and allows for less respiratorydead space, and requires less material for manufacture of the maskitself. Provision of material gradients provides for increased comfortand improved fit in areas of the mask by controlling pressuredistribution where differential pressure during contact of the mask withthe face would otherwise cause discomfort.

The method of manufacture incorporates the use of facial scanningtechniques (pictures, video, laser scanning, etc.) to define a surfaceas the basis for crafting a CPAP mask using a 3D printer. Use of 3Dprinting, also referred to as additive manufacturing, incorporatesadditional benefits such as elimination of material waste duringmanufacturing and quick fabrication of customized articles ofmanufacture.

The mask of an illustrative example incorporates at least two differentmaterials having distinct material properties such as modulus andductility, wherein the materials are changed over in one or moreseamless gradients. One company, Metamason, has discussed using a 3Dscan of the patient's face in order to generate molds that can be usedto fabricate custom masks. However, this process requires the 3D scan tobe transmitted to a fabrication plant where the molds for a mask aremade using 3D printing, and masks are made using a combination ofmolding and casting processes. A simpler process would be to generatethe masks directly by the use of 3D printing. The material gradients maybe incorporated into the mask through a portion of the thickness of themask or the entirety of the thickness of the mask; or across ahorizontal direction (when the mask is situated on the patient's faceand the patient is standing or sitting upright) or a portion of ahorizontal direction; or across a vertical direction or portion of avertical direction. Combinations of any of these are suitably combinedand multiple gradients in a single direction, or combination ofdirections, are incorporated into the masks of the invention. Further, agradient combines in some embodiments more than two different materials.For example, a single gradient may proceed, in a selected direction,from a first material composition to a second material composition andfinally to a third material composition. Various materials are suitablyincluded in different gradients, wherein the type of gradient isdetermined by the customized fit required.

While not particularly limited as to the number of materials employed inthe gradient, in some embodiments two or more materials having differentproperties of modulus, elasticity, glass transition temperature, degreeof crystallinity, ductility, softening point, melt flow index, and thelike or two or more different material properties are employed in thegradients imparted to the masks. In some embodiments, three or morematerials, for example up to ten different materials, or four to sevendifferent materials, are suitably employed.

In some embodiments, the transition between materials over the gradientis rapid over a selected distance; in other embodiments the transitionbetween materials is gradual within the same distance. In general, theone or more gradients are characterized by the lack of a discernibleboundary between materials, where the boundary is not seen with thenaked eye or apparent upon physical/tactile inspection. A structureformed in an additive process where material composition and/orproperties change from one location to another of the article caninclude gradients by avoiding abrupt transition. In contrast, an insertmolded piece, for example, will generally have a non-gradual, andnon-gradient, transition at the borders of the insert piece and themolding material. The inclusion of peripheral or secondary elementswhich are adhered or bonded to an article which incorporates a gradienttransition does not negate the gradient nature of the article which hasthe gradient transition. For example, as also discussed below, someembodiments include a mask foot having gradient transitions from softerto firmer or more structural materials, while also including a separatecap or port which is attached in a subsequent bonding step. Suchembodiments include a gradient structure even though there is also oneor more abrupt transitions.

The one or more material gradients are suitably applied employingadditive manufacturing using a printer that is capable of printing twoor more materials having different properties. In some embodiments, thematerials are added by melting the materials and allowing solidificationafter application of a printed layer. In other embodiments, a liquid orsyrup of curable materials are applied as printed layers and each layeris cured to result in a solid polymer prior to application of asubsequent layer. In some such embodiments, crosslinking of one or morematerials is also accomplished, wherein degree of crosslinking issuitably controlled by functionality of the liquid or syrup applied ineach layer or the treatment (irradiation, for example) of each layer.

In some embodiments, the additive manufacturing is carried out whereinblends of two or more materials are suitably formed prior to deposition.Thus, where a gradient is desired, mixing ratios of two or morematerials may be adjusted with each addition of a layer to result in thedesired gradient of deposited material. It will be appreciated that two,three, or more different materials may be suitably included in a blendfor any given area of addition to give the manufacturer complete controlover the material gradient.

Additive manufacturing provides customization for maximum patientcomfort, while the gradients enable control of rigidity of the mask.These features are highly beneficial for any type of facial mask, othertypes of masks, such as oxygen delivery masks or masks used forresuscitation or anesthesia applications or snorkeling/diving masks.

Another use of seamless compliant gradients may include the use of smallamounts of harder (higher modulus, lower ductility, or both) materialsto form the skeleton of the mask that would also include softer (lowermodulus, higher ductility, or both) materials. This approachincorporates a horizontal gradient of materials to create a customizeddistribution of pressure at the area of skin contact while using avariety of shapes to make that contact. This may result in bettercomfort and safety while using the mask.

In terms of clinical benefit, softer materials at skin contact withcustomized gradients transitioning to stiffer materials both in thevertical and horizontal directions as well as through mask thicknessprovides both excellent fit and control of pressure distribution at theskin-mask interface. Customized pressure distribution results inimproved mask performance combined with improved comfort. Improvingpatient comfort leads in turn to better mask tolerance and bettercompliance with treatment recommendations.

A further advantage of the invention is that the masks can be printedwith customizable color options incorporated. Thus, custom decorationsor logo designs are easily incorporated in the mask. Yet anotheradvantage of the invention is that the process overall is easy for anyphysician and patient to use without the need for cumbersome molds orfacial impressions, and provides a rapid progression from facialscanning/measurement to finished mask. For some implementations, anotheradvantage of the invention is that no inventory needs to be stored; eachmask is made on demand, so only a supply of materials for printing needto be kept at the manufacturing site.

FIG. 1 shows a flow chart for an illustrative method of making acustomized facial mask. The illustrative begins at block 20, where aperson's face is scanned by one or more techniques including digitalphotography, video, laser scan, and the like in a manner that capturesthe contours of the patient's face. For example, an image may becaptured, as indicated at 22 using photography or video capture.Alternatively, as shown at 24, a scanning or interrogation system mayuse laser or other imaging system to scan the surface contours of apatient. Subsurface characteristics may also be captured by usingmultiple imaging modalities, so that areas of tissue with bone andcartilage may receive different treatment in the final mask design, byproviding, for example, softer or firmer materials in those regions,than areas of softer tissue having subcutaneous fat or muscle. Aphysician input may be used in block 20 as well to generate fiducialpoints in the captured scan or image, for example, identifying the edgesof the lips and eyes, nostrils or other points of possible interest, tofacilitate a mapping of areas of greater and lesser likely patientmovement, tissue softness/hardness, etc.

Using the inputs gathered during facial scanning 20, a three-dimensional(3D) model of the patient's face is generated at block 30. The 3D modelmay include an outline of areas of interest, as indicated at 32, whichmay be generated directly from captured or scanned data, or may includephysician inputs. The facial topography 34 including surface contoursand areas identified as (or determined by use of multiple imagingmodalities) firmer or softer tissue may be identified. Areas ofpotential motion 36, for example near the lips or eyes, may also bemapped.

Next the contours of facial contact are identified in block 40. Theseareas may be determined by (optionally) first noting the type of mask tobe formed at 42, for example, whether a full-face mask or nasal mask forCPAP, a mask for other medical purposes (an oxygen mask), or a mask forwatersports (snorkeling or diving). Element 42 is optional; someembodiments will be dedicated to a single purpose—that is, thephysician's office may simply make a single type of CPAP mask and haveno need to make, for example, a diving mask. Using this input 42, themethod then selects the contours of facial contact from the 3D model, asindicated at 44.

The method then includes generating a design output, as indicated at 50the design output 50 may include mapping of areas of softer areas, thecontour of the tissue interface, the depth or thickness of materials asshown at 52, as well as gradients 54 to use in transitioning from softerto stiffer regions 56 and the mapping of stiffer regions. The designoutput may include features to facilitate or include a connector 58. Thedesign output may also include manufacturing details related to whetherthe mask is intended to prevent ingress of water, as in for watersports,or egress of pressurized air, as would be the case for a CPAP mask, asindicated at 60. The design may be different based on block 60 by, forexample, providing an inward flare at the tissue interface to preventair egress, or an outward flare at the tissue interface to prevent wateringress. It is noted that the design output 50 for an illustrativeembodiment includes both softer areas contoured for tissue contact 52and harder or stiffer regions 56 to maintain overall shape andstructure, with one or more seamless gradients 54 therebetween.

Finally, as indicated at 70, the mask is manufactured, preferably by a3D printing process. Next, the mask may be cured, cleaned and/orsterilized, as fits the needs of the application and user. The mask maythen be provided to its user.

FIG. 2 is a schematic view of a mask contact surface 110 situated on ascanned face 100 to show how the anatomical points of the face 100 areused to define an outer boundary 112 and inner boundary 114. Maskcontact surface 110 is shown as defined by several points in referenceto face 100.

Outer boundary 112 is defined by point 112-1 (4 mm below the nasion),point 112-2 (2 mm medial to the crunc lacrim), point 112-3 (6 mm lateralfrom the rhinion), point 112-4 (7 mm lateral to the alar facial groove),point 112-5 (superior to the corner of the mouth and resting on thenasolabial fold), and point 112-6 (1 mm above the vemillion border atthe midline). Inner boundary 114 is defined by point 114-1 (2.4 mm belowthe nasion), point 114-2 (1 mm lateral to the rhinion), point 114-3 (1mm lateral to the alar sidewalls), point 114-4 (1 mm inferior to thetermination of the alar sidewalls), point 114-5 (midway between points114-3 and 114-4 and 1 mm lateral to the alar sidewalls), and point 114-6(midline 1 mm below the columell-labial angle). These pointscollectively define an outer boundary 112 and an inner boundary 114 thatmay be smoothed using a “best curve fit” algorithm. This will ensuresmooth curvature of the defining boundary lines. These specificdistances are merely illustrative and may vary.

These points 112-1 through 112-6 and 114-1 to 114-6 may be identified byany suitable manner. For example, the facial imaging may automaticallygenerate these points by, for example, identifying bony structuresduring facial imaging itself, for example by overlaying an X-ray imageor thermal imaging with a visible image. In an alternative, thephysician may place stickers or use a marker to create dots, forexample, at specific points on the patient's face prior to imaging toenable one or more fiducial points to be identified. The points may alsobe auto-generated by finding fiducials at the edges of the eyes, noseand/or lips.

The area between the inner and outer boundary lines of FIG. 2 definesthe skin contact surface of the mask. The contact surface mask is thusidentified on the computer generated 3D facial surface and is designedto have features matching the inverse contours of the facial surface.The embodiment of FIG. 2 identifies a mask contact surface 110 that is 2cm over the bridge of the nose at its widest and 0.7 cm lateral to thenasion. It will be understood by those of skill that these and otherdimensions will fluctuate from a mask to mask depending on individualfacial anatomy of the user.

The contact surface of the mask contacts the patient's face within theboundaries described with respect to FIG. 2 and has a three-dimensionalshape, referred to herein as the mask foot, that proceeds in aperpendicular direction from the facial area to contact the remainder ofthe mask, referred to herein as the mask body. The mask foot is taperedas it proceeds from the facial contact surface toward the mask body. Oneor both of the mask foot and the mask body may include materialgradients to provide a gradient of modulus in one or more directions.The material gradients are characterized by the substantial absence ofdistinct interfaces.

FIG. 3A shows one example of a cross section 201 of a lower portion of amask foot 200, taken along line 3-3 of FIG. 2. The cross section 201 isa generally triangular shape with concave sides allowing for reductionin materials use while allowing for greater surface area contact. Thesides of the cross section 201 follow the form of a hyperbola of theequation y=1/x as defined by Cartesian coordinates. The base (skincontact area) may follow the shape of an inverted parabola of theequation

y=−x ²

where x is defined between −0.25 and 0.25. This will give the foot across sectional shape approximated by FIG. 2A. Thus, the cross section201 has base length 202 of 0.7-2.0 cm, height 203 of 1.0 cm, and apexwidth 204 of 0.2 cm.

Extending the foot cross section of FIG. 3A to a 3-dimensional formresults the shape approximated in FIG. 3B. FIG. 3B shows a mask foot 200that would form the basic seal for the mask that would extend around thenose, having base area 210 and apex area 220. Base area 210 contacts theface during use. In some embodiments, the materials used to form maskfoot 200 of FIG. 3B having cross section 201 of FIG. 3A include twodifferent materials that are printed then cured using UV light, suchthat a gradient of the two materials are formed. In some suchembodiments, the base 210 of FIG. 3B consists essentially of 100% TangoPlus FLX930 with Shore A hardness of 26-28 after cure, and transitionsin a substantially linear gradient from base 210 to apex 220 whereinapex 220 consists essentially of 100% VeroClear RGD810 having a Shore Dhardness after cure of 83-86. Both Tango Plus FLX930 and VeroClearRGD810 are commercial photopolymers for 3D printing available fromStratasys; other materials may be used. The elasticity modulus ofTangoPlus is estimated around 150-300 MPa while the elasticity modulusof VeroClear is 2000-3000 MPa. Thus, the elasticity modulus at 0.5 cmbase height, or ½ total foot height, is approximately 1200 MPa. In thisembodiment, the gradient transition is affected from base to apex. Othermaterials and gradient designs are also envisioned.

This gradient transition from base to apex of the mask foot yields asubstantial improvement in comfort and fit. However, one of skill willenvision modifications to the basic form shown in FIGS. 3A, 3B thatwould allow for further improvements. For example, rather than asymmetric foot cross sectional shape, an elongated asymmetrical crosssection such as that shown in FIG. 3C would reduce the overall deadspace within the mask and allow for the body of the mask to settlecloser to the skin surface when in use. FIG. 3C shows an asymmetrybetween first side 222 of cross section 220 and second side 222 of crosssection 220. During use, first side 222 of a 3-dimensional mask footbased on cross section 220 faces the external side of the mask, whilesecond side 222 faces the interior of the mask. The asymmetrical designof FIG. 3C has the same baseline as the mask foot 200 shown in FIGS. 3A,3B but the apex is shifted medially and centered at 30% of the totalwidth as measured starting from the midline edge of the foot crosssection 220. The concave arcs of the foot medially and laterally aredefined using the apex line as the Y axis and the base as the X axis andusing hyperbolic forms as noted above. In this design, the pressureexerted by the mask upon the skin may be more localized medially.

Uneven pressure distribution caused by the use of cross section 220 ofFIG. 3C may be overcome by the use of a core skeleton that woulddistribute such pressure evenly along the base of the foot. The basicshape of this designs is shown in FIG. 3D, wherein cross section of maskfoot 230 includes core skeleton 232. In some embodiments, core skeleton232 is printed during manufacture, for example by printing a thirdmaterial while the two gradient materials are printed and cured tosubstantially surround core skeleton 232. In other embodiments, coreskeleton 232 consists essentially of 100% VeroClear RGD810 throughout,wherein the core skeleton 232 is present within the otherwise lineargradient as described for mask foot 200. Alternatively, core skeleton232 is a member, such as a metal member, that is placed in the printarea and the two gradient materials are printed and cured so as tosurround the core skeleton 232.

In another modification, the core skeleton configuration of FIG. 3Dincludes a modulus gradient proceeding from exterior to interior,instead of or in addition to the modulus gradient traveling from base toapex. In one such embodiment, the core skeleton consists essentially ofVeroClear and is situated approximately 1 mm below the surface of themask foot. A “skin” consisting essentially of 100% TangoPlus covers theentirety of the mask foot at a depth of 1 mm from the surface. A lineargradient proceeds from 100% TangoPlus to 100% VeroClear over a 1 mmdistance towards the interior of the mask foot. This suggests that theelasticity modulus at a depth of 1.5 mm below the mask surface in anydirection would approximate 1200 MPa.

Another mask foot modification that is particularly advantageous from acosmetic and materials use standpoint is employing a modified mask footshape in the area of the mask foot that contacts the bridge of the nose.This modification calls for extending the mask foot at the “ankle” sothat the apex runs inferiorly and more closely to the anatomic nose,reducing the amount of material needed and giving a more pleasantaesthetic look and feel. This modified mask foot profile is shown inFIG. 3E.

In FIG. 3E, the core skeleton 242 of mask foot 240 is the same as ofFIG. 3D above. However, the concave shape of the mask foot arising fromthe outer boundary will follow a curve defined by the portion of ahyperbola of y=1/x where x is between 1 and 3. The concave portion ofthe mask foot arising from this inner boundary will be defined theparabola y=x² where the y axis is defined by two points, the first pointwhere the mask foot base and mask foot outer surface meet and the secondpoint is any point along the arc equidistant between the angle definedby the line described by the base of the mask foot and the linedescribed by the point of outer and base surface contact and the outerapex termination point. In some embodiments, the modified mask footprofile of FIG. 3E includes a modulus gradient proceeding from exteriorto interior, wherein a “skin” consisting essentially of 100% TangoPluscovers the entirety of the mask foot at a depth of 1 mm from thesurface. A linear gradient proceeds from 100% TangoPlus to 100%VeroClear over a 1 mm distance towards the interior of the mask foot.This suggests that the elasticity modulus at a depth of 1.5 mm below themask surface in any direction would approximate 1200 MPa.

These modifications are useful in various combinations. For example, amask foot that incorporates both the designs described in FIG. 3C andthat described in FIG. 3E may be suitably employed in a single maskfoot. Use of such a design increases the performance of the mask inavoiding leaks, because mask leaks are known by those of skill to occurprimarily over the bridge of the nose and, when using a full face masksthat cover both nose and mouth, over the soft portions of the cheek.Thus, in some embodiments, a nasal mask that incorporates mask footdesign of FIG. 3E over the bridge of the nose and mask foot design ofone of FIG. 3A, FIG. 3C or FIG. 3D, or a combination of two or morethereof for the remainder of the mask contact area is suitably employed.

FIG. 4 shows one embodiment of a combination mask design. Referring toFIG. 4, the mask foot design of FIG. 3E is employed in mask 300 over anupper zone 310 having outer boundary 312 and inner boundary 314 anddefined by the outer curve running from first outer boundary point 312-1through second outer boundary point 312-2 to third outer boundary point312-3, inner curve running from first inner boundary point 314-1 throughsecond inner boundary point 314-2 to third inner boundary point 314-3,and by the lines running from first outer boundary point 312-1 to firstinner boundary point 314-1 and from third outer boundary point 312-3 tothird inner boundary point 314-3. In some embodiments, upper zone 310 isincludes a material gradient proceeding from exterior to interior asdescribed for FIG. 3E.

Further in the illustration of FIG. 4, the mask foot design of FIG. 3Cis employed in lower zone 320 having outer boundary 322 and innerboundary 324 and defined by the outer curve running from first outerboundary point 322-1 through second outer boundary point 322-2 to thirdouter boundary point 322-3, inner curve running from first innerboundary point 324-1 through second inner boundary point 324-2 to thirdinner boundary point 324-3, and by the lines running from first outerboundary point 322-1 to first inner boundary point 324-1 and from thirdouter boundary point 322-3 to third inner boundary point 324-3. In someembodiments, lower zone 320 is characterized by a material gradientproceeding from base to apex as described for FIG. 3B.

For the embodiment in FIG. 4, transition zones 330 are defined by theareas described by the four first boundary points (312-1, 314-1, 322-1,and 324-1) and the four third boundary points (312-3, 314-3, 322-3, and324-3). In this embodiment, the transition zones 330 provide atransition or gradient between the design of FIG. 3E, and the design ofFIG. 3C. Such a transition or gradient can proceed from the inclusion ofa core skeleton in upper zone 310 to the absence of a core skeleton inlower zone 320. However, in some embodiments, the transition zones 330have no core skeleton element; in other embodiments, transition zones330 have a core skeleton element that ends at the end of the transitionzone. In any of these embodiments, transition zones 330 may include amaterial gradient aside from the presence or absence of a core skeletonelement.

In this example of FIG. 4, gradients may operate in all threedirections, X, Y and Z, as indicated at 340. In the X direction, atleast the transition zone 330 may be stiffer closer to the bridge of thenose than it is closer to the nostrils. In the Y direction, the innerand outer edges of the lower zone 320 may be more flexible than thecenter portion thereof in one or more layers. Finally, in the Zdirection, the overall mask 300 may be softer at the tissue interfacethan it is away from the patient's skin.

The material gradient of transition zones 330 of FIG. 4 is designed andadapted to provide a smooth transition between the material gradientsselected for the upper zone 310 and lower zone 320. Thus, in the exampleset forth in FIG. 4, the material gradient transitions from theexterior-to-interior gradient of upper zone 310 to the bottom-to-topgradient of lower zone 320. Additionally, the shape of the mask footcross section is transitioned, in the embodiment shown in FIG. 4, fromthe cross section shape 240 of FIG. 3E to the cross section shape 220 ofFIG. 3C. Such transitions may be effected within the directions for the3D printing by varying the material composition from one position toanother of the printer output. The output may be varied continuously orin steps such that a single mask 300 may have various zones withdiffering material properties, with at least two of the zones meetingacross a gradient transition.

It is an advantage for some embodiments of the present invention thattwo or more material gradients are applied in a single construction suchas that described in detail for FIG. 4. It is a further advantage thattransition areas between zones having different material gradients,different shapes, or both are easily provided.

Once the description of the mask foot has been computationally rendered,the remaining body of the mask will be formed. The mask body may beformed by considering the topical geography of the face alreadydescribed by initial computer surface modeling. In some embodiments, onthe other hand, since the mask body is separated by the mask foot fromthe patients face, the mask body can be standardized to the overall sizeof the patient's face, rather than being unique to the patient.

In some embodiments, the facial contact surface is further defined bythe outer edge of the circumferential line formed by the apex of themask foot as shown in FIGS. 3A-3E, and in other embodiments a differentmask foot having a different apex thickness is employed. This region mayhave a thickness in the range of 1-4 mm, with 2 mm preferred. Themodeled surface may be trimmed electronically or automatically to thedesired shape.

Where the mask is a CPAP mask, a standard tubing attachment port isadded with the lowest circular edge approximately 6-10 mm above theinterior edge of lowest point of the mask foot and preferably centeredwithin the mask construction. The mask body in some embodiments may beseparately fabricated, with the tubing attachment port integral to themask body which can then be attached to the mask foot by adhesive, heator other process. In another embodiment, the mask body can be overmoldedonto the mask foot, with a location for a tubing port built into theovermold. In yet another embodiment, the mask body and mask foot are 3Dprinted as one, with space left for the tubing port at an appropriatelocation. In some embodiments, the mask body is formed entirely of a lowmodulus material, such as cured VeroClear RGD810, with no materialgradient in the mask body, though the transition from the softer maskfoot to the mask body may include a gradient of higher and lower modulusmaterials.

A full face mask design is also easily envisioned using the specificparameters set forth above for FIGS. 1, 2A-2E, and 3. The mask footboundaries would be defined according to anatomic landmarks similar tothe process describe in connection with FIG. 1 above. For full face maskcircumferential foot construction, design strategies including two ormore zones such as the upper and lower zones described in FIG. 3 couldbe used to reinforce support not only over the bridge of the nose butalong the cheek line where full face mask leaks are likely.

In a working embodiment, a patient specific mask was generated by firsttaking three photos of the patient's face at different angles. Thesephotos and information therefrom were entered using a Solidworks®software tools to generate a facial rendering. The targeted areas of thepatient's face illustrated by the inner borders (114-1 to 114-6) andouter borders (112-1 to 112-6) highlighted in FIG. 1 were then selectedfor entry as the base topography for the 3D-printer model using standardStratasys® 3D printer software. Several masks have been built andpatient testing showed the prototypes were well tolerated by thepatients.

The materials described above are available for use with the Stratasysline of 3D printers and therefore these particular materials were chosenfor prototyping and development. However, other materials may be used.Of interest here is that the tissue contacting or tissue-adjacentmaterials be biocompatible and sufficiently soft and flexible tofacilitate patient comfort, with one or more gradients of differentmaterials having distinct material properties defined as the mask footis built upward, away from the patient tissue, toward a more sturdy andstructurally resilient mask body. If desired, at the tissue interface acoating may be applied to enhance patient comfort, for example a thinlayer of soft foam.

One example of a mask foot having more than two distinct zones is shownin FIG. 5. Mask foot 400 is characterized by at least four differentzone types. Upper zone 410 and lower zone 420 are distinct and separatezones wherein each zone 410, 420 has a different shape, a differentmaterial gradient, or both. Zone 430 and zone 440 are different fromzone 410 in terms of shape, material gradient, or both. Zones 430, 440are the same or different in terms of shape, material gradient, or both.Zone 450 and zone 460 are different from zone 420 in terms of shape,material gradient, or both. Zones 450, 460 are the same or different interms of shape, material gradient, or both. Zone 450 is different fromzone 430 in terms of shape, material gradient, or both. Zone 460 isdifferent from zone 440 in terms of shape, material gradient, or both.In some embodiments, zones 430 and 440 are transition zones totransition one or more of material gradient or shape from zone 410 tozones 450 and 460 respectively. In some embodiments, zones 450 and 460are transition zones to transition one or more of material gradient orshape from zone 420 to zones 430 and 440 respectively.

One example of a “minimalist” mask design that also maximizes pressuredistribution and minimizes leaking during contact with the face is shownin FIG. 6. Mask 500 includes mask foot 501 and nose cap 502. Mask foot501 has first zone 510 and second zone 520; mask foot 501 further hasouter boundary 512 and inner boundary 514. Outer boundary 512 is definedby the curved line formed by point 512-1 (approximately 2.4 cm below thenasion), outer boundary points 512-2 (union of nasal and maxillaryplains, approximately 1 cm below point 512-1), outer boundary points512-3 (approximately 1 cm lateral to the alar side walls), and outerboundary point 512-4 (approximately 0.5 cm above the vermilion border atthe midline). Inner boundary 514 is defined by the line defined by thealar nasal edge, point 512-1 (midline and approximately 1 mm below thecolumell-labial angle). Again, the dimensions provided are merelyillustrative.

In some embodiments, nose cap 502 rests fully across the surface of thenose. In other embodiments, nose cap 512 partially covers the nose. Insome embodiments, nose cap 502 has a wedge shaped cross section, whereinthe cap is has a thickness of about 0.5 mm starting near point 512-1 andincreasing in thickness as it proceeds in a direction toward outerboundary point 512-4. Maximum wedge thickness of about 3 mm is reachedat the alar nasal edge. In some embodiments, nose cap 502 consistsessentially of VeroClear RGD810 at the non-skin contact surface,consists essentially of TangoPlus FLX930 at the skin contact surface,and includes a material gradient proceeding from the skin contactsurface to the non-skin contact surface. The gradient is linear in someembodiments.

At the junction between nose cap 502 and inner boundary 514, atransition gradient (not shown) is provided in a radial direction, thatis, the direction proceeding from the edge of the nose cap 502 towardinner boundary 514 over the portion of inner boundary 514 that isconnected to the nose cap 502. The transition gradient is determined bythe particular material composition at each radial point of connection.In some embodiments, the transition gradient is linear. In otherembodiments, the transition gradient is nonlinear, with a greatermaterial ratio change per unit of distance occurring closer to thecenter of the nose cap 502 and a less material ratio change per unit ofdistance occurring closer to inner boundary 514.

The design of nose cap 502 provides for contact of the lower half of thenose with the mask foot, resulting in an excellent fit and a muchgreater area of pressure distribution than previously possible, and thussuperior comfort. Meticulous control of material gradients results insuperior performance with respect to fit and comfort with minimalleaking.

Second zone 520 is constructed using the mask foot design described inFIG. 3A or FIG. 3C wherein base length 202 (as shown in FIG. 3A) isabout 1 cm, height 203 is about 1.0 cm, and apex width 204 is about 0.2cm. Mask foot second zone 520 further includes a material gradient suchas the gradient described in connection with FIG. 3B (the 3D mask footfor which FIG. 3A is a cross sectional view).

Not shown in FIG. 6 is a dome portion of that extends from the edgeportion of nose cap 502 not connected to inner boundary 514 (the alarnasal edge) to the inner boundary 514 proximal to lower zone 520. Thedome portion may have a uniform thickness throughout. In someembodiments the thickness is in the range of about 1-5 mm, and in oneembodiment, about 2 mm. In some embodiments the dome portion is curvedover its entirety to smoothly meet the connecting surfaces of the maskfoot 501 and nose cap 502. In embodiments, no material gradients areincorporated into the dome portion. A standard tubing port (not shown)may be incorporated into mask 500 in similar fashion to that describedfor FIG. 4.

Mask 500 provides minimal “dead space” with maximum pressuredistribution over the skin while incorporating an excellent fit. Thedescribed design elements are obtainable because of seamless gradientdesigns and meticulous material gradient control.

As previously noted, one or more embodiments of the present inventionmay provide one or more of improved mask comfort; improved seal forlower leak rates into or out of the mask; less material needed formanufacture than for conventional manufacturing methods; better patientcompliance with prescribed therapy for medical masks such as CPAP;customized decoration; no need for facial mold or impressions; and aneasy process for both physician and patient; and no need to storeinventory.

In some embodiments, a home kit may be designed to allow a patient totake photographs or video at home to enable a distant manufacturingfacility to fabricate a CPAP mask. For example, a home kit may includedigital cameras disposed in a desired array. In another example, a homekit may include one or more stickers that a user can apply to their faceto facilitate imaging by providing fiducials across the patient's face.For example, one or more stickers could be implemented as nasal stripsor adhesive bandage-type materials for placement at instructed locationson the patient's face, allowing digital correction of video or stillimages provided by a patient. As an alternative to a home kit, aphysician's office or a sleep clinic may be provided with a photo-booth,an image capture apparatus, or stickers for creating fiducials on thepatient's face, to allow the patient to be fitted for a mask in aclinical setting. A mobile solution, such as a van or truck having asuitable setup may also be provided. A web-based system could make useof a patient's webcam by instructing the patient to simply turn theirhead back and forth a couple of times while the webcam captures video;if the captured video is inadequate, a real-time interface couldindicate to the patient what went wrong, if, for example, the patientdid not keep their head level or turned too far in one direction. Theseexamples avoid the need to obtain a mold of a patient's face (or partthereof) in order to construct a patient-unique, custom CPAP mask.

Also described herein is a method of fabricating custom made orthoticmembers, and custom made orthotic members that include one or morematerial gradients. Orthotics is a specialty within the medical fieldconcerned with the design, manufacture and application of orthoses. Anorthosis (plural: orthoses) is “an externally applied device used tomodify the structural and functional characteristics of theneuromuscular and skeletal system”—(ISO 8549-1:1989). Orthoses are usedin applications including but not limited to: control, guide, limitand/or immobilize an extremities, joint or body segment for a particularreason; to restrict movement in a given direction; to assist movementgenerally; to reduce weight bearing forces for a particular purpose; toaid rehabilitation from fractures after the removal of a cast; and tootherwise correct the shape and/or function of the body, to provideeasier movement capability or reduce pain.

Types of orthoses include, but are not limited to clavicular andshoulder orthoses, arm orthoses, elbow orthoses, arm-wrist orthoses,hand orthoses, foot orthoses (shoe inserts, or insoles), ankle-footorthoses, knee orthoses, rehabilitation braces and prophylactic braces,spinal orthoses, and the like. In some embodiments, the orthosis is foran animal other than a human; for example, dog and horse orthoses arecommonly employed after an injury or to treat a condition in the animal.

It is an advantage of the current methods and articles that eachsituation is treated with ease both to provide a custom fit of theorthotic member, and to provide material gradients to control pressuredistribution during use. Control of pressure distribution isaccomplished at the skin/orthotic member interface to result in greatercomfort and effectiveness of the orthotic member wherein non-optimizedpressure differentials lead to side effects such as soreness, irritationof skin, muscle, tendons, and/or bone, or even bone spurs, tendinitis,bursitis, and the like. The increased comfort experienced by patientswhen using the custom made orthotic members also leads to greaterpatient compliance and thus a more effective treatment overall.

One example of a custom made orthotic member is an insole, which is anorthotic member that addresses the plantar area of the foot. A custommade insole that conforms to the shape of the plantar area of the humanfoot and controls pressure distribution during walking, running, and/orjumping provides for improved fit and greater comfort. As describedabove, custom manufacturing by additive methods (3D printing), requiresless material for manufacture of the orthotic member itself.Additionally, in some embodiments, material gradients are optimized forrunning or walking or jumping or some other specific mode of movement,for people who engage in activities involving a relatively largeproportion of such movement. Examples include but are not limited tolong distance running, basketball, cross-country skiing, and the like.

As with the foregoing descriptions, the plantar region of the foot isscanned using digital photos, videos, laser scanning, etc. to generate acomputer model of the foot. In some embodiments, scanning of the plantarincludes an analysis of pressure points and pressure distribution acrossthe plantar during engagement in certain activities, such as walking orrunning Such differential pressure is a source of great discomfort tomany people. After scanning, the surface of the orthotic member ismanipulated to describe a custom fitted orthotic useful as a supportdevice within a shoe or other device such as a brace.

In some embodiments, the insole employs a thin core of stiffer materialto support areas of the foot undergoing greater stress during standing,walking or running An example of such a design would be the use of astiffer materials gradient to support the heel, arch, and metatarsalareas and softer materials gradient for cushioning throughout theremainder of the design.

Referring to FIG. 7, a top view 610 of one example of an insole 600 isshown. By “top view” it is meant that the view shows the side of theinsole that would contact a human foot. Insole 410 includes non-gradientportion 611 and gradient portions 612. Gradient portions 612 includeheel portion 614, metatarsal portion 616, and arch portion 618. Heelportion 614 and metatarsal portion 616 each include a core region havinga non-gradient composition having a first ratio of two polymericmaterials, and gradient region surrounding the core region in alldirections wherein a linear gradient in polymer ratio proceeds radiallyto a second ratio of the two polymers at the surface of portions 614,616. The second ratio is the ratio of polymers present in non-gradientregion 611. The gradients and core compositions of heel portion 614 andmetatarsal portion 616 are the same or different, in variousembodiments.

In one representative embodiment, the core of the heel region 614 andmetatarsal region 616 includes a 25/75 (wt/wt) mix of TangoPlus FLX930and VeroClear RGD810, wherein the cured mixture has a modulus of1500-1800 MPa. This modulus provides excellent support while beingflexible enough to bend slightly with the surface changes required forwalking Regions 614, 616 include a 3 mm core region of the 25/75 mixtureand include a materials gradient both vertically and horizontallyrelative to the disposition of insole 600 during use. The verticalgradient of regions 614, 616 extends 2 mm above and below the coreregion to end at a 75/25 (wt/wt) mix with the surface modulus beingapproximately 900 MPa. The materials gradient is linear from core regionto surface region. This means the majority of the insole 610 will beapproximately 7 mm in thickness (defined as the direction perpendicularto the top view as shown), the exception being the arch portion 618 asdescribed below.

Thus, the materials gradient portions 612 at the heel portion 614 andmetatarsal portion 616 both include a core region having a 25/75 wt/wt(1800 MPa) ratio of the two polymers described, and transition over agradient region to a final ratio of 75/25 wt/wt (900 MPa) of the twopolymers over a total of 5 mm distance in any direction from the coreregion. The gradient transition is linear in every direction proceedingfrom the core regions outward over the gradient regions; that is, thegradient is radial. The non-gradient portion 411 is 75/25 wt/wt of thetwo polymers, having modulus of 900 MPa throughout. Non-gradient portion611 is contoured to the plantar of the scanned foot.

Another gradient portion 612 is arch portion 618. Similarly to heelportion 614 and metatarsal portion 616, arch portion 618 includes a coreregion having a 25/75 wt/wt (1800 MPa) ratio of polymers formed fromTangoPlus FLX930NeroClear RGD810, as described above. Dimensions of thecore region of arch portion 618 depend on individual anatomy and rangesfrom about 1 cm to 3.5 cm at its greatest thickness and proceeding anestimated 5-15 cm in length (length defined as the measurement takenfrom the tips of the toes to the back end of the heel of the foot). Thearch portion 618 core region dimensions are defined on three sides bythe surface of the foot making contact with the floor and medially bythe extension of the line of the arch from a 90 degree overhead view.The gradient region of arch portion 618 proceeding in a direction fromthe core region of arch portion 618 through the gradient region is 2 mmin all directions. The gradient region of arch portion 618 transitionslinearly from a ratio of 75/25 wt/wt (1800 MPa) at the core region to afinal ratio of 75/25 wt/wt (900 MPa) of the two polymers. Similarly, thehorizontal gradient with be linear over a 5 mm distance in alldirections except for medially. The medial gradient will be 2 mm so asto accommodate a better ergonomic fit inside the shoe or other device.

Several of the above examples focus on the use of a gradient within amaterial blend from a first material composition to a second materialtransition. In some embodiments, a gradient may be replaced with alattice, interleaved, or other structure to allow for a gradualtransition from one material to another. These lattice and interleavedpatterns may be used for a general transition between softer and stiffermaterials, such as in a mask foot, or may be used to transition into andaway from structural elements such as a frame or backbone for a mask.

A first example is shown in FIG. 8, with a transition from a softermaterial 700 to a harder material 702 across a transition zone 704characterized by interleaving “teeth”. As the cross section occupied bythe softer material 700 is reduced and replaced by the harder material702 as one set of teeth narrows and the other widens, a gradualtransition takes place. For the structure in FIG. 8, it may be desirableto also transition the edges of the teeth according to a gradienttransition, to avoid the creation of locations of greater stress, strainor fatigue.

FIG. 9 shows another transition, this time with a piece 720 having alattice of quadrilaterals 722, 726 of a relatively harder materialwithin a main composition of softer material 724. The thickness of the“beams” of the quadrilaterals changes from thin beams at 722 to thickerbeams at 726, imparting a transition from flexible to stiff asillustrated at 728. The lattice structure provides a backbone to thesoft material 724, without exposing the edges thereof. A 3D printingprocess is one very useful way to impart this sort of transition andbackbone structure, avoiding the complexity of an insert moldingprocess. Part of the purpose, in this instance, is to enable thebenefits of insert molding to be realized without requiring the overheadand process controls associated with a molding process.

FIG. 10 shows another transition, this time having a background piece750 of soft material with discs or balls of harder material, withsmaller pieces 752 on the right transitioning to larger pieces 754 onthe left.

FIGS. 11-12 show illustrative tissue contact designs. In an exampleshown in FIG. 11, a number of curves are provided as the facial mask 800come close to the tissue surface 802. The curvatures 804 provide addedflexibility and softness, allowing for tissue movement. As noted above,a soft material such as felt or foam may be provided in a thin layer aswell to enhance comfort. FIG. 12 shows another example, with a facialmask 850 tapering as it approaches the tissue surface 852 by including athin region 854. In addition to structurally thinning the material, agradient may be used here as well. Given the taper to thin region 854,it may be desirable to make the thin region 854 stiffer than the areaaway from the tissue surface. These examples in FIGS. 11 and 12 may alsobe used to provide a surface treatment on a mask foot as shown invarious of the above examples.

FIG. 13 shows an illustrative mask coupled to an air supply hose using aball joint. The mask 900 may be a nose cup mask or a full face mask. Acoupler 904 connects the hose 902 to the mask 900. The coupler 904 maybe attached to the mask by adhesive or bonding, or may be snap fit ontoa mask having a built-in connection point (see mask 950 in FIG. 14,below). By using a ball-type coupler 904, the tube 902 can turn aboutthe mask 900 in the direction indicated at 906, allowing the user tomove more freely than may be the case with a fixed coupler. Othercoupling mechanisms may be used instead.

FIG. 14 shows an illustrative working example. A “nose cup” style maskis shown which covers only the patient's nose and forms a seal around itin order to supply air. The individual mask is custom fit to thepatient's face. First a computer model of the patient's face isgenerated using 3D scanning The mask is then idealized by 3D printingwith an Objet Connex 3D printer, which has the capability to manufactureobjects that have varying material properties within the object.

In the working example, the 3D printer capability is used to construct amask having a acrylic-like rigid shell which gradually transitions to asofter silicone-like material in the areas of facial contact. By thiscombination the mask is both rigid enough to hold its shape and flexibleenough to be comfortable and adaptable to the wearer's face as it moves.These material transitions take various forms. In the area over thebridge of the nose, the material gradient goes inward from all surfaces,creating a sort of rigid “bone” inside the seal with softer materialaround it. This allows the seal to be soft enough for comfort and alsorigid enough to grip the bridge of the nose for support and positioning.In the area over the upper lip, the gradient goes from soft to rigidstraight out from the lip, allowing more flexibility so that the maskcan conform more easily to any movements in the patient's lip.

Due to the nature of the computer model used in fabrication of theworking embodiment, areas of consistent material properties are definedand provided to the 3D printer as an assembly of layers withincrementally varying rigidity. By using thin layers, a very smoothmaterial transition is obtained.

The finished mask is shown at 950. A tube connector is shown at 952,with adjacent vent holes at 954. In accordance with an embodiment, theregion of tissue contact 956 is generally softer and more flexible thanthe mask cap 958, which defines the volume of air within the mask (alsoreferred to as the dead space), which can be minimized by keeping agenerally close fit. Handles 960 are shown for illustrative purpose aswell.

A cutaway view along line A-A is shown at 970, and the individuallyprinted layers are shown at 972 to 982. During manufacture, a gradientis formed in small steps with each progressive layer being of adifferent material composition than a previous layer. For example, thesoftest, first layer 982 is printed first, followed by a second layer980 which is slightly softer and formed of a different materialcomposition. The drawing is illustrative in nature; more than the 6layers shown may be used in some embodiments, with dozens of layers in asingle printed article. By using an additive process, each subsequentlayer becomes indistinguishable from the prior layer during the process,at least from the perspective the user.

In some embodiments, there is no apparent change when viewed with thenaked eye, or when manipulated, as the layers are added one upon anotherto provide a soft outer surface transitioning to more structured layersand harder elements. Thus, for example, the layer printed at 972 isformed of a hard material that allows for coupling of a tube/hose via acoupler as shown above in FIG. 13, for example, including the snap fitfeatures on the connector 952. One way of describing the structure isthat the mask 950 is formed using an additive process in which a firstlayer, such as layer 982, is suitable to a first purpose (skin/tissuecontact) and a second layer, such as layer 972 is suitable to a secondpurpose (the snap fit coupler), wherein the first layer is poorly suitedto the second purpose (as it is too soft) and the second layer is poorlysuited to the first purpose (as it is too inflexible), with a gradienttransition (such as layers 974, 976, 978 and 980) therebetween which isnot perceptible to the naked eye.

FIG. 15 shows an illustrative example of the selecting of inner andouter boundaries based on identified fiducial points. The relativepoints selected are based on the area around the nose 1000 of a patient.To begin, the edges of the nose are identified with the corners, 1, 2,from which the midpoint 3 can be identified. The base 4 of the nose isidentified as well. By choosing the base 4 at the midpoint 3, differentshaped noses can be accommodated—it is not simply assumed that thepatients nose is a straight line between corners 1, 2. From thesefiducial points 1, 2, 3, 4, a set of inner boundaries A, C and E andouter boundaries B, D and F identified.

The method is also shown in block-flow. At block 1010, points 1 and 2are identified, with point 3 found at 1012. Point 4 is identified at1014. Next, the inner boundaries A, C and E are set at 1016. DistancesA-B, C-D, and E-F are then set, as well as associated angles/vectors foreach 1018. For examples, longer or shorter distances can be set takinginto account the patients skin texture (oily, dry, wrinkled), the natureof the patient's underskin composition (minimal versus much collagen),with a wider distance used for patient which variable skin—wrinkled, dryskin lacking collagen may call for a wider distance, for example. Someof these factors may be obtained through a patient questionnaire inaddition to the use of imaging technology. The angles/vectors used maybe, for example, set more horizontally for a patient with a rounder face(as measured by using, for example, the distance from chin to foreheadin comparison to the distance between the ears or the outer edges of theeyes, cheek or jawbones) when calculating the nose contours. Anadditional factor may be the distance from the line 4 to the patient'slips; a narrower distance A-B would be used for a shorter distance tothe lips. Then the outer boundaries B, D, and F are set at 1020.

Other measurements that may be incorporated into mask sizing include,for example, the distance between the bilateral crunc lacrum, betweenbilateral crunc lacrum and the nasion, distance from a point 1centimeter inferior to the nasion to the bilateral nasal maxillaryjunction (horizontally), the bilateral distance from the zygomatic archto the nasal ridge apex (where the point on the zygomatic arch may bedefined as directly inferior to the lateral margins of the eyes). Inadditional examples, the points of interest may include the points onthe zygomatic arch directly inferior to the bilateral pupils, then tothe nasal ridge apex. In another example, the bilateral points directlyinferior to the crunc lacrum and resting over the nasal maxillaryjunction, including the distance to the nasal ridge apex. Otherlocations of interest may be defined, with the object of establishingreference points to define the lines and shape thereof for contactsurface on the face of a patient.

Another illustrative example is shown in FIG. 16, highlighting the useof the gradient structure at the points of skin contact. A mask is shownat 1100, and a section along line A-A is shown at 1102. Further detailviews are shown, with B highlighting the structure 1104 for contactingthe root and bridge of the nose, and C highlighting the structure 1106for contacting the philtrum. In the further detail views, structure 1104includes a soft material at 1112 and a harder structural material 1110joined together by gradient 1114. Structure 1106 also includes a softmaterial at 1122 and harder structural material at 1120, joined togetherby gradient 1124. The soft materials 1112 and 1122 may be similar incomposition, or different, if desired. For example, material 1122 may bemore flexible than material 1112 in order to accommodate patientmouth/lip movement during sleep. The structural material 1110 and 1120may be similar or different as well; in an example the two 1110 and 1120are the same and are generally acrylic.

It should be noted that the addition of color to one or more layers cancreate a visible transition between layers of different materialproperties. The intent in several of the embodiments shown above is toprovide a smooth transition of material properties. Decorativeadditions, such as color, should be ignored when contemplating thenature of a transition from one material to another.

Some alternatives may include other breathing support apparatuses suchas nasal pillows or a nasal cannula. A nasal pillow may include acone-shaped outer surface to make contact with the interior of the narisor nostril of a patient. Individual cones or pillows may bedesigned/shaped by beginning with a scanning technology to obtain ashape of the lower portion of the nose and nasal entrance of thepatient. As with the nasal mask approach, a three-dimensional model canbe obtained and 3D printing used to realize the design output of themodeling, with softer regions defined at the portions of the nasalpillow which are to contact patient tissue, and a gradient to more rigidmaterials farther away. The interior of each pillow can be connected toa tube containing pressurized air (for apnea-related uses) or containingtherapeutic materials such as oxygen enriched air, nitrous oxide, or aninhalant depending on the needs of a particular application.

For example, a nasal pillow may be designed by obtaining information onthe shape and size/location of the naris, the columella, thecolumella-labial angle and the upper lip to construct custom nasalpillow masks. Such a mask would entail two cone-like surfaces makingcontact with each naris, with each cone having a circumferentialcurvature to match each naris, based on the captured images for thepatient. Typically each cone may extend into the naris by about 1 to 5mm, with 3 mm preferred, both horizontally and vertically from the innernaris edge. Each cone could then extend externally to cup the alar andcolumella portions of each naris in a circumferential manner, again forabout 1 to about 5 mm, with 3 mm preferred. Each cone may descend about3-10 mm, with 5 preferred, to connect to tubing. In an example, agradient construction would transition from very soft surfaces and edgeswithin the naris to the descending portion of the cones to have a strongstructure for tube attachment while being soft at the point of tissuecontact. In another example, the gradient structure could connect a verysoft material at the skin contact portion of the cone and, over adistance of about 2 mm, to a more rigid material. In one example, theTangoPlus FLX930 material noted above is used at the tissue interface,and a 50/50 mix of FLX930 and VeroClear RGD810 is used for the innerwall of the cone, providing a linear transition from a modulus of 300MPa at the skin contact to about 1200 MPa in the interior cone wall. Alip foot may be added as well to link the two nasal pillows and allowthe mask to rest on the upper lip of the patient.

Another illustrative example takes the form of a nasal cannula. Byobserving the anatomic surfaces of the patient and using 3D printingwith gradient technology as described above, a nasal cannula fordelivery of breathable oxygen may be provided. Using a digital or otherimage or 3D scan of the lower portion of the nasal entrance, the shapeof each naris, the columella, the contours of the naris-labial junction,and the basilar inlet of each naris may be obtained. This topographywould then be used to print a nasal cannula for smooth and gentlecontact with the nasal inlet and upper lip of the patient. Such acannula design may be constructed to occupy about 25-33% of thecross-sectional area of each naris inlet.

An inner portion of such a nasal cannula can include an oxygen port ofabout 3 mm diameter, which is similar to existing equipment. The roundedinner portion would use a harder material (such as the 50/50 blend ofFLX930 and RGD810 noted above), and changes across a gradient to theouter, tissue contacting portion of the cannula to a softer material(such as a 100% FLX930 material). Each cannula may be approximately 5-15mm long (with 10 mm preferred), and 3-7 mm wide (with 5 mm preferred),though such dimensions may also be customized. The cannulas may extendinto the naris for about 3-6 mm, with 4 mm preferred. The oxygen portsmay be rounded to avoid irritation inside the nose, and another gradientmay be used from the tip to the interior of the cannula to assist withreducing irritation. Upon exiting each naris, the cannula can bend inthe range of 25 to 60 degrees, or more likely 34-45 degrees to alignwith the naris-labial junction.

The area of tubing between and connecting to each oxygen port of suchcannulas can be contoured to the shape of the patient's anatomy at thebase of the columella and columella-labial angle. The ports may be inthe range of 3-8 mm apart. The cannula can then be attached to standardtubing.

Because 3D printing can be used on-site to make a specialized nasalpillow and/or nasal cannula, more comfortable and secure placement canbe obtained for example in the hospital where some such devices arecommonly used, without requiring a wide variety of shapes and sizes tobe maintained in stock.

Each of these non-limiting examples can stand on its own, or can becombined in various permutations or combinations with one or more of theother examples. The above detailed description includes references tothe accompanying drawings, which form a part of the detaileddescription. The drawings show, by way of illustration, specificembodiments in which the invention can be practiced. These embodimentsare also referred to herein as “examples.” Such examples can includeelements in addition to those shown or described. However, the presentinventors also contemplate examples in which only those elements shownor described are provided. Moreover, the present inventors alsocontemplate examples using any combination or permutation of thoseelements shown or described (or aspect thereof), either with respect toa particular example, or with respect to other examples shown ordescribed herein. In the event of inconsistent usages between thisdocument and any document incorporated by reference, the usage in thisdocument controls.

In this document, the terms “a” or “an” are used, as is common in patentdocuments, to include one or more than one, independent of any otherinstances or usages of “at least one” or “one or more.” Moreover, in thefollowing claims, the terms “first,” “second,” and “third,” etc. areused merely as labels, and are not intended to impose numericalrequirements.

Method examples described herein can be machine or computer-implementedat least in part. Some examples can include a computer-readable mediumor machine-readable medium encoded with instructions operable toconfigure an electronic device to perform methods as described in theabove examples. An implementation of such methods can include code, suchas microcode, assembly language code, a higher-level language code, orthe like. Such code can include computer readable instructions forperforming various methods. The code may form portions of computerprogram products. Further, in an example, the code can be tangiblystored on one or more volatile, non-transitory, or non-volatile tangiblecomputer-readable media, such as during execution or at other times.Examples of these tangible computer-readable media can include, but arenot limited to, hard disks, removable magnetic or optical disks,magnetic cassettes, memory cards or sticks, random access memories(RAMs), read only memories (ROMs), and the like.

The above description is intended to be illustrative, and notrestrictive. For example, the above-described examples (or one or moreaspects thereof) may be used in combination with each other. Otherembodiments can be used, such as by one of ordinary skill in the artupon reviewing the above description.

The Abstract is provided to comply with 37 C.F.R. §1.72(b), to allow thereader to quickly ascertain the nature of the technical disclosure. Itis submitted with the understanding that it will not be used tointerpret or limit the scope or meaning of the claims.

The invention illustratively disclosed herein can be suitably practicedin the absence of any element which is not specifically disclosedherein. While the invention is susceptible to various modifications andalternative forms, specifics thereof have been shown by way of examples,and are described in detail. It should be understood, however, that theinvention is not limited to the particular embodiments described. On thecontrary, the intention is to cover modifications, equivalents, andalternatives falling within the spirit and scope of the invention. Invarious embodiments, the invention suitably comprises, consistsessentially of, or consists of the elements described herein and claimedaccording to the claims.

What is claimed:
 1. A facial mask comprising a first material and asecond material and a material gradient in at least a portion of themask, the material gradient transitioning from the first material to thesecond material.
 2. The facial mask of claim 1 wherein the firstmaterial is a polymeric material suited to a first purpose, and thesecond material is a polymeric material suited to a second purpose andnot to the first purpose.
 3. The facial mask of claim 2 wherein thefirst material is a relatively softer material well suited to contactwith the face of a patient, and the second material is a harder materialwell suited to providing a structure and shape to the mask.
 4. Thefacial mask of claim 1 further comprising two or more gradients.
 5. Thefacial mask of claim 1 wherein the first and second materials differ inone or more of modulus, elasticity, glass transition temperature, degreeof crystallinity, ductility, softening point, or melt flow index.
 6. Thefacial mask of claim 1 wherein the mask is a CPAP mask.
 7. The facialmask of claim 1 wherein the mask is made by additive manufacturingwithout the use of insert molding or casting.
 8. The facial mask ofclaim 1 wherein the material gradient is characterized by a lack ofdiscernible boundary insofar as there is no visible boundary to thenaked eye.
 9. The facial mask of claim 1 wherein the material gradientis characterized by a lack of discernible boundary insofar as a boundarycannot be identified under manual inspection.
 10. A method ofmanufacturing a facial mask, the method comprising obtaining a set offacial contours of a person's face by one or more of digitalphotography, video, infrared, or laser scanning; optimizing a set ofmask contours for an area where a mask will come in contact with theperson's face; and constructing a mask using an additive printingprocess including a first layer of a first material having firstproperties and a second layer of a second material having secondproperties and a material gradient between the first and second layersin at least a portion of the mask, the material gradient characterizedby the lack of a discernible boundary between the first and secondmaterials.
 11. The method of claim 10 wherein constructing step isperformed such that the first material is a polymeric material suited toa first purpose, and the second material is a polymeric material suitedto a second purpose and not to the first purpose.
 12. The method ofclaim 11 wherein the constructing step is performed such that the firstmaterial is a relatively softer material well suited to contact with theface of a patient, and the second material is a harder material wellsuited to providing a structure and shape to the mask.
 13. The method ofclaim 12 wherein the constructing step is performed by introducing athird material having third material properties different from each ofthe first and second materials and joining the third material to atleast one of the first and second materials using at least a secondgradient characterized by a lack of discernible boundary to the firstand/or second materials.
 14. The method of claim 10 wherein constructingstep is performed using first and second materials that differ in one ormore of modulus, elasticity, glass transition temperature, degree ofcrystallinity, ductility, softening point, or melt flow index.
 15. Themethod of claim 10 wherein the constructing step is performed withoutthe use of insert molding or casting.
 16. The method of claim 10 whereinthe additive process is performed such that the material gradient ischaracterized by a lack of discernible boundary from the first materialto the second material insofar as there is no visible boundary to thenaked eye from the first material to the second material.
 17. The methodof claim 10 wherein the additive process is performed such that thematerial gradient is characterized by a lack of discernible boundaryfrom the first material to the second material insofar as a boundarycannot be identified under manual inspection.
 18. The method of claim 10wherein the step of optimizing a set of mask contours comprisesidentifying one or more fiducial points of the set of facial contoursassociated with one or more of the patient's nose, lips, or eyes andsetting an inner boundary and an outer boundary relative to theidentified fiducial point or points.
 19. A continuous positive airpressure facial mask for the treatment of sleep apnea built according tothe method of claim
 10. 20. A apparatus for assisting in the breathingof a patient built according to the method of claim 10.